Hydraulic jack



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United States Patent:

HYDRAULIC JACK Millard A. Rhoads, St. Joseph, William D. Unruh, Stevensville, and Walter Graber, Benton Harbor, Mich., assignors to Auto Specialties Manufacturing Co., St. Joseph, Mich, a corporation of Michigan Application May 2, 1951, Serial No. 224,214 4 Claims. (CI. 6052) This invention relates to hydraulic jacks.

Among the objects of the present invention are to provide a single valve which is not only automatically operated by a predetermined pressure in the ram cylinder to open and release this pressure, bypassing a portion of the liquid in the ram cylinder back to the reservoir, but

also to provide a construction wherein this same valve.

is manually operable at any desired time to relieve the liquid in the ram cylinder back to the reservoir whereby to permit the return of the load lifting member back to partial or complete nonloading lifting position.

Yet another object of the invention resides in providing a manually operable relief valve operating mechanism associated with the manually operable handle that is used to operate the liquid pumping mechanism for the ram cylinder and particularly wherein two alternate types of operating mechanisms are provided.

Yet another object of the invention resides in providing a simple type of spring operated relief valve adapted to open upon the creation of a predetermined excess pressure in the ram cylinder for bypassing a portion of the liquid in the ram cylinder back to the reservoir.

Yet another object of the invention resides in providing a novel construction of means whereby the ram cylinder and reservoir are pivotally attached to the side walls of the main frame so that the forward end of the ram itself is directly pivotally connected to the pivotally mounted load lifting member whereby to provide a more direct and positive means for raising and lowering the load lifting member from the operation of the ram.

Yet another object of the invention resides in pivotally mounting the ram cylinder and pivotally connecting the front end of the ram to the pivotally mounted load lifting member for accomplishing foregoing arrangement wherein the relief valve and its operating lever are built into the same pivoting structure.

Fig. l is a side elevational view of a hydraulic operated. jack and showing the load lifting member in dot dash lines in a raised position;

Fig. 2 is a plan view of the hydraulic jack with a portion of the figure broken away; p i

Fig. 3 is an enlarged vertical sectional view taken on the line 3-3 of Fig. 2; I

Fig. 4 is a horizontal sectional view taken on the l1ne 4-4 of Fig. 3; r

Fig. 5 is a vertical cross sectional v1ew taken on the line 55 of Fig. 2;

Fig. 6 is a'longitudinal vertical sectional view taken on the line 6-6 of Fig. 2; I

Fig. 7 is a fragmentary vertical sectional v1ew taken on, the line 77 of Fig. 6;

Fig. 8 is a fragmentary sectional view showing a IIlOdlfied form of relief valve operating mechanism;

Fig. 9 is a cross sectional view taken on the line*9.9 of Fig. 8; t

Fig. 10 is a side elevational view taken directly behind the side frame and showing the ram cylinder and reservoir in elevation;

Fig. 11 is a view similar to Fig. 10 showing the ram cylinder and reservoir in a changed position from that shown in Fig. 10; I

Fig. 12 is a perspective view of the ramcyllnder and reservoir and its associated parts; a

Fig. 13 is a partial perspective view of the lower end of the operating handle;

Fig. 14 is a sectional view showing a modification of the valve 118; and

Fig. 15 is a vie showing still another modification of the valve. i

Referring now to the drawings in detail, the particular jack in which the embodiment of the present invention is incorporated comprises preferably a body or frame consisting of two elongated side plates 2 and 4 suitably bolted together at intervals along the length of the side plates by tie rods 6, 8 and 10. These rods are suitably attached together by means of nuts 12 threading upon 10 the threaded ends of such rods. In addition, these side frames 2 and 4 are also united by other pivotal connections hereinafter to be described. At the front end of the jack the two side plates 2 and 4 are formed with suitable bearings to receive a front axle 14 carrying at 15 its outer ends two wheels or rollers 16 and 18 by which the front end of the jack is movably mounted. In addit1on, toward the rear end of the jack there is provided, one on each side, a caster wheel subassembly consisting of wheel 22, wheel fork, axle 20, castering trunnion shaft, 20 mounting bracket, attaching bolts and nuts, and caster trunnion bearings and nuts.

Likewise having a pivotal bearing in the upper central portion of the two side frames 2 and 4 is a relatively rugged cross' shaft 26 held in position therein by the nuts 28 and 30 on which cross bar 26 is pivotally mounted the elongated lifting member 32 shown in Fig. 1. On the extreme front end of this lifting member is pivotally mounted, as at 34, the usual type of load lifting saddle 36. This saddle rigidly carries a depending arm 38 piv- 30 ot ed as at 40 to a pair of spaced elongated links 42 and 44. The extreme opposite ends of these links 42 and 44 are pivoted to the side plates 2 and 4 as at 45 and 47 whereby to provide, with the lifting member 32, a parallel linkage system to maintain the load support 36 in horizontal position in any raised or lowered position of the load lifting member 32.

A ram cylinder and ram are pivotally mounted as a unit on and between the side plates 2 and 4 of the basal frame and means are provided which pivotally connect the outer end of the ram directly with a portion of the pivotally mounted load lifting frame 32 so that upon operation of the hydraulically operated ram, the load lifting lever 32 will be positively shifted about its pivotal axis 26. The hydraulic unit so mounted between the frame members 2 and 4 is shown in Fig. 12 as comprising a motor or ram unit 46 which is shown in detail in Figs. 3, 4 and a power unit 48 and a head 50 of generally circular conformation and provided with internal threads 52 and 54 '(Fig. 3) threadedly to receive the ram cylinder 50 56 and to provide a hydraulic reservoir 58 between the ram cylinder 56 and the reservoir tube 60. The outer end 62 of the head 50 is provided with the usual packmg 64 whereby to provide an anti-leak packing for the ram rod 66 which passes therethrough. The inner end of the ram, as at 68, is provided with any type of ap- {fl proved leather or synthetic rubber gasket or cup to prevent the passage of oil past the ram head spacer 70. The body of the power unit 48 is provided with internal passages interconnecting the high pressure pump cylinder 0 with theram cylinder and with a bypass passage to the reservoir 58. The unit 48 (see Fig. 4) is provided with a ma or bore 72 (see Fig. 3) for the reception of a high pressure pump cylinder 74 which threads as at 76 into the internal threads of the bore 72. A high pressure pump piston 78 operates within this cylinder 74 and is M provided with the usual anti-leak gaskets 80 of desired construction. The body of the power unit 48 is provided with a relatively small passage 82, see Fig. 3, therethrough which connects with an internal vertical passage 70 or bore 83 formed in the body. This vertical passage 83 has a pair of valve seats formed therein, the same being a smaller seat 84 and a larger valve seat 86. Valve balls. 88 and 90 mate in perfect contact on these valve seats. The lower end of the passage 83 connects with a passage 92 formed in the same body, which passage iff; connects directly with the reservoir 58. The passage 83 at its opposite end extends all the way through the body of the power unit and is capped or closed by a screw plug 94. The power unit body is provided with an additional passage 96 that connects with the ram cylinder and,

in addition, the power unit body is provided with an oppositely disposed passage 98, see Figs. 3 and 4, which lies directly opposite the passage 96. This passage 98 connects with a valve chamber 108 formed in the power unit body. In addition the power unit body is provided with a bore 102 (see Fig. 4) which connects with the bore 83 hereinbefore described and this bore 102 is closed at the external wall of the body by a plug 104. This bore 102 connects the bore 83 with filler bore 106, see Fig. 4, which bore 106 terminates on the exterior wall of the body and is closed by a plug 108, see Fig. 12. This bore is used to fill the hydraulic reservoir 58 with working fluid. The valve chamber is provided with a bore 109, see Fig. 4, formed in the body of the power unit 48 which connects the valve chamber with transversely disposed bore 110 formed in the power unit body 48 which bore 110 connects as at 112 with reservoir 58. The external wall of the bore 109 is closed by a plug 114.

The valve chamber 100 as shown in Figs. 3 and 4 and passage 98 are substantially concentric. The intersection of end wall of chamber 100 and wall of passage 98 acts as a valve seat on which perfectly seats cone type poppet valve 118. The cone 118 is formed on the end of a stem 122. Stem 122 is guided in a bore formed in a screw plug 136 which screws into internal threads formed in a. hollow boss 128 formed in the end of the power unit bodyl The outer end of this valve stem 122 has a threaded end 125. This threaded end receives a couple of lock nuts 127 and an interposed yoke or fork member 129, as shown in Fig. 6, forming one end of a bell crank lever 130 which is pivoted as at 132 to a pair of lugs 134 formed on the end of the body of the power unit 48. A spring 135 coils around the shank of the valve stem 122 and abuts against the back of a disk formed on the stem 122 and to move with it. The chamber 100 in which the valve stem disk 120 and the valve 118 operate is closed by means of the threaded plug 136 which internally is formed to house the spring 135. A pair of ring washers 137 pressure seal the valve stem 122 and chamber 100.

As shown in Fig. 14, a modification of the valve is illustrated. In this form a ball valve 119 is used and the valve stem 122 is provided with a head 123 formed with a substantially semi-spherical seat or cage adapted to maintain the ball 119 centered on the central axis of the valve seat while permitting the ball 119 to open or shift outwardly away from its seat under the conditions described herein. This cage or seat 125 maintains the ball 119 from lateral movement relative to the valve seat. The head 123 forms a guide for the valve stem 122 and an abutment for the control spring 135.

In Fig. 15 still another modification of the valve is shown. Here the valve comprises a semi-spherical valve ititzrzli'ace 126 which is formed rigidly with the valve stem Mechanism for operating the bell crank is provided. In the present instance this is cooperatively associated with the elongated pivoted handle 140 (see Fig. 6). This handle is of dual purpose and is so constructed. Primarily the handle 140 is provided with a basal portion 142, provided with a pair of sockets 144 and 146, see Fig. 13, each to receive bearing pins 148.and which are press fitted in the handle and rotate with the handle in bushings 152 and 154 (Fig. 4), which bushings are stationarily mounted in side frames 2 and 4. In addition to the foregoing, the lowerpart 142-of the handle 140 is provided with a pair of spaced lugs 156 and 158 (see Fig. 13) which are suitably perforated as at 160 and 162 to receive pins 164 and 166 (Fig. 4) which are received in bores 168 and 170 as seen in Fig. 12, formed in a pair of links 172 and 174 which links in turn connect as at 176 and 178 to a, yoke 180. This yoke at its central portion is connected (see Fig. 4) as 2% 182 to the outer end of the high pressure pump piston The circular outstanding bosses 190 and 192 projecting oppositely from the power unit are provided with outstanding circular shoulders 191 which shoulders bear in correspondingly shaped and positioned openings in the opposed frame members 2 and 4. This is shown in Fig. 4. In addition such circular bosses 190 and 192 and the outstanding circular shoulders 191 are bored and threaded to receive pivot bolts 194 and 196 passing through basal frame members 2 and 4 to provide a detachable pivotal mounting for one end of the power unit. I

The high pressure pump piston 78, see Fig. 3, rec1procates in the high pressure pump cylinder 74 which is provided on its outer end with a suitable gasket 208 to provide a seal thereat.

The handle basal portion 142 extends rearwardly in the form of a hollow tube member 210 (see Fig. 6) and forms a socket for a sleeve 212, the same being connected together at 214 by means of the screws shown. The opposite end of the sleeve 212 receives internally thereof a second sleeve 216 which at its outer end is provided with a cross handle 218 and is connected to the sleeve 216 by the screw 220. The handle portion 218 is hollow centrally and receives therethrough a valve operating handle 222 which turns in a bearing 224 in the main handle 218. This handle 222 is provided with a pin 226 which passes through an end 228 of a handle rod 230. The internal end of the handle 222 is provided with a lug 232 which engages with an arcuate lug 234 formed on the operating handle 218. The purpose of this lug is to prevent the turnable handle from being turned beyond a predetermined arcuate amount. The inner end of the turnable rod 230 carried by the turnable handle 222 is provided with a detachable connection 238 to an eccentric member 240 having a turnable bearing 242 in the base portion 142 of the lower portion of the operating handle. This eccentric 240 contacts the bell crank lever 130 at a position along the center line of the main hinge pins 148 and 150 for the handle so that upon proper rotation of the handle 222, regardless of the vertical position of the main handle 140 the lever will be shifted to pull the valve stem 122 outwardly against the tension of its spring 135 manually to move the valve 118 from its seat whereby fiuid under pressure in the ram cylinder can flow from the ram cylinder through the passage 96 to the bore 83, through the bore 98 into the valve chamber and thence by way of passage 109 and relief passage 110 back to the reservoir 58 thereby manually releasing the pressure in the hydraulic cylinder to permit the ram to return and lower the lifting member of the jack.

Independently of this manual operation, when the pressure on the load lifting member and thence on the ram 66 reaches a predetermined amount wherein more pressure will exert excessive stress on the jack assembly as a whole, the back pressure created will act against the disk 120 and hence against the spring 135, causing the spring to collapse and also cause the valve 118 to move from its seat automatically to bypass the liquid back to the reservoir. The manual operating mechanism for this valve in no wise prevents the automatic operation.

Upon operation of the main handle mechanism 218 and 212 and 142, and its connection as at and 178 and 176, the pump piston 78 is actuated back and forth in the pump cylinder 74 to build up pressure in the ram cylinder through the passageways hereinbefore described. Upon retraction of the high pressure piston, liquid is drawn from the reservoir 58 through the passage 92, see Fig. 3, past the ball check valve 88, into the high pressure cylinder and then upon reverse movement of the pump piston 78 the liquid is forced through the port 82 into the passage 83 and past the ball check valve 90 through the port 96 and thence into the high pressure ram cylinder. chamber. The valve ball 90 is normally spring pressed on its seat by means of a spring 87.

As an alternative means for releasing the valve 118 from its seat there is shown a construction in Figs. 8 and 9 which comprises the same operating rod 230 hereinbefore described which is controlled by the handle 222. The inward end of the rod 230 as shown in Fig. 9 is provided with a toothed pinion 242 which cooperates with a sleeve member 244 (see Figs. 8 and 9) having annular teeth 246. This sleeve member has on its forwardend a collar 248 which is attached thereto by a set screw 250. A spring 252 surrounds a cross pin 254 which cross pin is mounted in the pivot pins 152 and 154 (see Fig. 8) hereinbefore described. This cross pin also formsa guide and supports threaded sleeve 246 whereby the sleeve will shift back and forth on the cross pm 254 by the operation of the pinion gear 242. Upon rotation of this gear 242, the sleeve 246 will move back and forth, thereby moving the collar 248 back and forth to shift the slot and pin connection 256. This pin 256 is mounted on the end of a bell crank lever 258 which is similar to the bell cranklever 130 hereinbeforedescribed and operates the relief valve mechanism in the, same manner. 2

, It will thus be seen by means of the foregoing invention there has been provided a hydraulically operated jack preferably of the wheel type wherein a positive pivlifting arm is provided, which connection permlts of the utilization of a unit package comprising the ram cylinoted connection between the ram and the pivoted load der, ram and the valve mechanism carried thereby with simple disconnectable connections to the high pressure pump cylinder and the handle mechanism for operating the high pressure pump cylinder. In addition there is provided an extremely simple type of a single valve which operates both automatically as a relief valve for automatically relieving the hydraulic pressure in the ram cylinder when a predetermined pressure therein is created and which valve is likewise manually operable from a shiftable member carried by the pivotally mounted handle that operates the high pressure pump cylinder whereby upon operation of the manual control the same valve is manually operable to release the same to permit the passage of the hydraulic operating fluid from the ram cylinder back to the reservoir so that the load lifting member may be released and descend to nonload lifting position or to any intermediate position.

It is obvious that various changes may be made in the specific embodiments set forth without departing from the spirit of the invention. The invention is accordingly not to be limited to the specific embodiments shown and described but only as indicated in the following claims.

The invention is hereby claimed as follows:

1. A hydraulic operating unit comprising a body housing having a ram cylinder, a pump cylinder and a fluid reservoir, a ram reciprocably mounted in said ram cylinder and projecting therefrom, a pump piston reciprocably mounted in said pump cylinder and projecting therefrom, an actuatable member operatively connected to the projecting portion of said pump piston to operate the same, valves and valve controlled passages in said body housing for directing hydraulic fluid from the reservoir to the pump cylinder and from the pump cylinder into the ram cylinder to actuate the ram on actuation of said pump piston, said body housing having means forming a valve chamber, fluid passages in said body housing connecting said ram cylinder to said valve chamber and said valve chamber to said reservoir, the valve in said chamber controlling communication between said last mentioned passages, said valve having a stem provided with a disk-like member also disposed in said valve chamber, said disk-like member having an internal diameter slightly less than the diameter of the inner walls of the valve chamber, spring means normally operative to urge said disk-like member in a direction to close said valve, a housing for said spring means adjustably mounted at one end of said valve chamber to determine the ram cylinder pressure at which said valve opens to relieve pressure in said ram cylinder, a bell crank pivotally mounted on said body housing and having one end connected to said valve stem, a control member carried by said actuatable member, said control member being mounted on said actuatable member for rotation relative thereto and having a cam shaped free end portion engaging said bell crank whereby to swing said bell crank and open said pressure relieving valve on rotation of said control member relative to said actuatable member.

2, An hydraulic operating unit comprising a ram cylinder having a base therefor, a fluid reservoir therefor, a ram shiftable lengthwise of the cylinder under hydraulic pressure, a pump piston and a cylinder including an actuable member for operating said-pump piston, valved connections operable on the actuation of said piston for forcing liquid into the ram cylinder to actuate the ram, said cylinder base having a valve chamber and conduit means from said valve chamber to said ram cylinder and to said reservoir, a valve controlling the flow of liquid from said ram cylinder into said chamber and to said reservoir, said valve having a disk-like member includ ing a valve stem having a portion mounted in said chamber, a spring encircling the stem and operable normally to press said valve against its seat, said last mentioned spring being adjustable to permit said valve to open at a predetermined pressure in said ram cylinder to relieve pressure in said ram cylinder, a bell crank lever having a portion engaging the stem of the valve, said pump piston actuator including a pivoted handle for actuating said pump, said pivoted handle including an elongated turnable member mounted thereon and turnable relative- 1y to said handle, the inner end of said elongated member having an eccentric portion engaging the free end of said bell crank lever whereby upon operation of said turnable portion said bell crank is operated to withdraw the valve against the tension of its spring from the valve seat to permit fluid in the ram cylinder under pressure to flow from the ram cylinder back to the reservoir, said elongated turnable member on said pump actuator having a control member at the outer end of the handle for turning said elongated turnable member.

3. An hydraulic operating unit comprising a ram cylinder having a base therefor, a fluid reservoir therefor, a ram shiftable lengthwise of the ram cylinder under hydraulic pressure, a pump piston and a cylinder including an actuable member for operating said pump piston, valved connections operable on the actuation of said piston for forcing liquid from the pump cylinder into the ram cylinder to actuate the ram, said cylinder base having a valve chamber therein and a conduit from said valve chamber to said ram cylinder and to said reservoir, a valve controlling the flow of liquid from said ram cylinder into said valve chamber and to said reservoir, a valve stem having a disk-like member mounted in said chamber, a spring encircling a portion of the valve stem and abutting said disk-like member normally to press said valve against its seat, said last mentioned spring being adjustable to permit said valve to open at a predetermined pressure in said ram cylinder and relieving pressure in said ram cylinder, a bell crank lever mounted pivotally with respect to said cylinder base and having a portion engaging the shank of the valve, said pump piston actuator including a pivoted handle for actuating said pump, said pivoted handle including an elongated turnable member mounted thereon and turnable relatively to said handle, the inner end of said elongated member having an eccentric portion engaging the free end of said bell crank lever whereby upon operation of said turnable portion said bell crank is operated to withdraw the valve against the tension of its spring from the valve seat to permit fluid in the ram cylinder under pressure to flow from the ram cylinder back to the reservoir, said elongated turnable member on said pump actuator having a control member at the outer end of the handle for turning said elongated turnable member, and a stop carried by said elongated actuator for said bell crank for limiting the turning movement of said elongated member by its actuator.

4. A hydraulic operating unit comprising a ram cylinder, a fluid reservoir, a fluid pump cylinder, a ram reciprocably mounted in said ram cylinder, 3. pump piston reciprocably mounted in said pump cylinder, a pump piston actuator operatively connected to said pump piston, valves and valve controlled conduits for directing the fluid from the reservoir to the pump cylinder and from the pump cylinder to the ram cylinder, means forming a valve chamber, a spring controlled pressure release and relief valve in said chamber, conduits connecting said chamber to said ram cylinder and said chamber to said reservoir to permit the passage of fluid from said ram cylinder to the reservoir on operation of said pressure release and relief valve, said pressure release and rellef valve having a stem portion projecting from said valve chamber, a bell crank lever having one arm engaging the stem of said valve, said pump piston actuator including a pivoted handle for actuating said pump piston, a control rod rotatably mounted on said handle for rotation on an axis extending lengthwise of the bandle, the inner end of said rod having an eccentric portion engaging the other arm of said bell crank lever to actuate said pressure release and relief valve upon rotation of said rod about said axis, said rod having a rotatable operating knob journaled on and projecting beyond said handle.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,263 Erickson et al. May 11, 1915 (Other references on following page) 7 UNITED STATES PATENTS Jakob Nov. 5, 1929, Hopkins June 23, 1931 Green May 5, 1936 Rosenberry Jan. 24, 1939 2,439,796- 2,ssw;.127

8 Ziskm Aug. 19, 1941 Strcuzr Sept. 26, 1944- Richards May 20, 1947 Dearslcy .J Apr. 20, 1948 Simmons May 22, 1951 

